The 60 days survival rate with the "early" strategy is estimated to be 45%. It is necessary to include 620 patients (310 per arm) to obtain a power of 90% to detect a survival improvement of 14% at day 60 with the "delayed" strategy (log-rank two tailed test, global significance level of 5%), with two blind interim analyses by independent observers at 90 and 180 deaths (group sequential approach of O'Brien-Fleming), and a estimated dropout rate of 10%.